Mouthpiece

ABSTRACT

Mouthpiece ( 1 ) having vestibular shield ( 21 ) overlapping a user&#39;s teeth and gums, gases passageway means extending through said vestibular shield allowing for the passage of said gases through mouthpiece and extra oral sealing ( 25 ) means associated with gases passageway, said passageway in use causes gases to be diffused (outlets  23, 24 ) when exiting from gases passageway. Mouth piece may have a noseflap to seal the user&#39;s nose or provide a passageway for user&#39;s nasal passages. Mouthpiece may have adjustment means to alter distance between said vestibular shield and said extra-oral sealing means.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference and made a part of thepresent disclosure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a system for oral delivery of gasespressurized above ambient, and in particular, to a system, including anovel mouthpiece, for the oral delivery of air or gases in continuouspositive airway pressure (CPAP) treatments of sleeping disorders such assleep apnoea.

2. Description of the Related Art

Sleep apnoea treatments have been significantly advanced with theintroduction of continuous positive airway pressure (CPAP) treatments.These treatments, as introduced, involve the supply of gases from agases supply or blower to a patient or user through a conduit and nasalmask to provide an elevated internal pressure in the user's airways toassist the muscles to keep the airways open. This air stream is providedto the user through a nasal mask applied over the nose and held in placeby a harness. This configuration has been almost universally adoptedbased on the well-known observation that humans show a decidedpreference for nasal breathing during sleep. For this reason, littledevelopment has been undertaken into other possible methods of providingthe pressurized air stream to a user.

Oral delivery is suggested in EP818213, which shows an apparatus fororal delivery of air in a CPAP treatment. The apparatus includes amouthpiece adapted to fit inside the mouth between the roof of themouth, the hard palate, and the tongue, and having a periphery that canbe gripped between the teeth. It is thought by the applicants that thisis significantly more intrusive than is necessary and is liable tomovement and consequent discomfort (although not outright removal) underthe relaxation of sleep. It has the additional disadvantage that withthe user fully relaxed, such as in the case of sleep, distension in theuser's jaw and subsequent opening of the mouth can reduce the sealingeffectiveness of the mouthpiece and reduce the efficacy of the CPAPtreatment.

The mouthpiece in EP818213 is gripped between the user's teeth; thus afurther disadvantage results in that the mouthpiece requires customorthodontic fitting to ensure that the mouthpiece matches the user'smouth and teeth layout. Custom orthodontic fitting is time consuming andremoves the capability of effective mass manufacture. Consequently, themouthpiece in EP818213 is expensive, creating a significant barrier tothe adoption of the device by the user.

A similar gases delivery mouthpiece, for use with a respirator, is shownin WO90/03199. WO90/03199 discloses an orthodontic device that isadapted to be gripped between the jaws of a user and to accommodate theuser's teeth within a series of upper and lower cavities. A base memberof the mouthpiece is shaped and fits against the hard palate of theuser. This mouthpiece again has the disadvantage of requiring customorthodontic fitting. Furthermore, as a result of the mouthpiece'ssubstantial thickness and size, the mouthpiece is substantially rigid inthe vestibule regions of the mouth. The mouthpiece is clamped in placeby an outer shield that engages the outside of the user's lips.

A paper by E Veres entitled “Clinical trial of an oral vestibular shieldfor the control of snoring” (Journal of the Dental Association of SouthAfrica, January 1993) describes the use of a shield intended to beretained in the vestibule of the mouth to seal the mouth and to promotenasal breathing which has been conventionally considered to be morebeneficial than oral breathing. Humidified CPAP treatments deliveredorally, however, actually derive greater benefit than those deliverednasally because secondary leakage through the nasal passages during oraldelivery is significantly less than oral leakage during nasal delivery.The shield depicted in the paper is formed from flexible ethylene vinyl.The shield is custom trimmed and is custom fitted by heating to amalleable temperature and deformed by applied pressure.

Other possible mouthpiece designs are shown for example by use in selfcontained underwater breathing apparatus systems, for example asdepicted in U.S. Pat. No. 4,862,909. This mouthpiece is a mouth guardtype and is clamped between the teeth. A flange extends both in front ofand behind the teeth.

Prior art mouthpieces are not well adapted for use in CPAP treatmentsbecause they are intended for conscious gripping by the user, and havebeen found subject to accidental removal with a user in a completelyrelaxed state such as sleep.

A further prior art mouthpiece that is of relevance is that shown inFIGS. 1 and 2, this mouthpiece is described in co-pending U.S. patentapplication Ser. No. 09/629,536. Referring to FIG. 1, the mouthpiece isillustrated including an extra-oral sealing flap 100 and intra-oralsealing flap 101. The extra-oral flap 100 in its natural bias is taperedfrom the breathing circuit connection 104; the wide-open end of which isshaped to conform to the facial contours around the outside of the mouthof a user. The extra-oral flap 100 is constructed of flexible material,such as silicone rubber. The outer flap 100 is seen in FIG. 2 in a bentback position. When the mouthpiece 102 is inserted into the mouth of auser, the outer flap 100 is intended to be in this bent back position toaid insertion. Prior to insertion, the outer flap is bent back by simplypressing on its outer periphery 106, until it snaps into the bent backposition, in which it will stay unaided.

The mouthpiece as shown in FIGS. 1 and 2 also includes a tonguedepressor 103 extending from the inner face of the intra-oral sealingflap 101. The tongue depressor 103 further includes a pair of verticallyextending spacers 105 which in use may abut against the roof of thewearer's mouth and ensure that the tongue cannot completely block theair passageway. This stops the sleeping user unconsciously blocking theoral passageway and reverting to nasal breathing.

With the prior art mouthpiece of FIGS. 1 and 2, while the tonguedepressor ensures that the tongue does not block the gases outlet, itprevents the user from moving their tongue to moisten the inside oftheir mouth, causing extreme dryness inside the user's mouth.Furthermore, the tongue depressor can prevent or restrict swallowing.Thus the mouthpiece of this invention has disadvantages that cause usersdiscomfort.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a system for oraldelivery of gases, and/or a mouthpiece for oral delivery of gases, whichgoes some way toward overcoming the above disadvantages or which will atleast provide the public with a useful choice.

In a first aspect the present invention consists in a mouthpiececomprising:

-   -   a vestibular shield having an inner surface and an outer        surface, said vestibular shield having a predetermined height        which will overlap a user's teeth and gums when positioned in        the mouth vestibule of a user;    -   gases passageway means extending from through said vestibular        shield allowing for the passage of said gases through said        mouthpiece;    -   extra-oral sealing means associated with said gases passageway        to assist with compression upon a user's face, gases diffusing        means associated with said gases passageway means and said inner        surface that in use causes said gases to be diffused when        exiting from said gases passageway.

In a second aspect the present invention consists in a system capable ofbeing used for oral delivery of gases to a user comprising:

-   -   gases supply means,    -   a gases passageway in fluid communication with said gases supply        means, and    -   a mouthpiece in fluid communication with said gases passageway        including an intra-oral sealing means and an extra-oral sealing        means and gases diffusing means.

In a third aspect the present invention consists in a system capable ofbeing used for oral delivery of gases to a user comprising:

-   -   a mouthpiece,    -   a breathing tube,    -   decoupling means for connecting said mouthpiece to said        breathing tube, and    -   means to diffuse gases associated with said decoupling means.

In a fourth aspect the present invention consists in a mouthpiececomprising:

-   -   a vestibular shield having an inner surface and an outer        surface, said vestibular shield having a predetermined height        which will overlap a user's teeth and gums when positioned in        the mouth vestibule of a user,    -   gases passageway means extending through said vestibular        allowing for the passage of said gases through said mouthpiece,    -   extra-oral sealing means associated with said gases passageway        to assist with compression upon a user's face, and    -   adjustment means to alter the distance between said vestibular        shield and said extra-oral sealing means.

In a fifth aspect the present invention consists in a mouthpiececomprising:

-   -   a vestibular shield having an inner surface and an outer        surface, said vestibular shield having a predetermined height        which will overlap a user's teeth and gums when positioned in        the mouth vestibule of a user;    -   gases passageway means extending from through said vestibular        allowing for the passage of said gases through said mouthpiece;    -   extra-oral sealing means associated with said gases passageway        to assist with compression upon a user's face,    -   nose attachment connected to at least part of the upper edge of        said extra-oral sealing means which in use covers or abuts said        user's nose.

To those skilled in the art to which the present invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will suggest themselves without departingfrom the scope of the invention as defined in the appended claims. Thedisclosures and descriptions herein are purely illustrative and are notintended to be in any sense limiting.

The invention consists in the foregoing and also envisages constructionsof which the following gives examples.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described withreference to the accompanying drawings.

FIG. 1 is a perspective view of a prior art mouthpiece having an outerflap in an “in use” position.

FIG. 2 is a perspective view of the prior art mouthpiece of FIG. 1 wherethe outer flap is bent back in a “locating” position.

FIG. 3 is a side elevational view of the system according to the presentinvention as being used by a user.

FIG. 4 is an exploded perspective view of a first form of the mouthpieceof the present invention including gases diffusing outlet.

FIG. 4A is an exploded perspective view of a first form of themouthpiece of the present invention, showing an abutment for use inlocating and retaining the mouthpiece in the mouth of the user.

FIG. 5 is a perspective view of the vestibular shield of the first formof the gases diffusing mouthpiece of the present invention.

FIG. 6 is a plan view of vestibular shield of the first form of thegases diffusing mouthpiece of the present invention.

FIG. 7 is a perspective view of a vestibular shield having channels orapertures to allow for moisture flow about the shield.

FIG. 8 is a perspective view of a mouthpiece having.

FIG. 9 is a perspective view of a mouthpiece with an outer flap havingan integral nose flap.

FIG. 9A is a cross sectional view of the mouthpiece of FIG. 9.

FIG. 9B is a cross sectional view of another form of a mouthpiece thathas a nose flap and nasal cannula.

FIG. 9C is a cross sectional view of yet another form of a mouthpiecethat has a nose flap and nasal cannula.

FIG. 9D is a cross sectional view of a further form of a mouthpiece thathas nasal cannula extending from it.

FIG. 10 is a perspective view of an alternative embodiment of an outerflap that has protrusions that assist in closing off a patient's nasalpassages.

FIG. 11 is an exploded perspective view of a second form of themouthpiece of the present invention having an alternative gasesdiffusing outlet.

FIG. 12 is a side cross sectional view of vestibular shield of the firstform of the gases diffusing mouthpiece of the present invention.

FIG. 13 is a side view of the vestibular shield of the second form ofthe gases diffusing mouthpiece of FIG. 11.

FIG. 14 is a side view of an elbow piece and associated tubing,connectable and to be used with any one of the embodiments of themouthpiece of the present invention.

FIG. 15 is a perspective view of a further form of an elbow piece,connectable and to be used with any one of the embodiments of themouthpiece of the present invention.

FIG. 16 is a cutaway view of the mouthpiece with split flow diffusingwith an outer flap in use.

FIG. 17 is a block diagram of a respiratory system according to thepreferred embodiment of the present invention.

FIG. 18 is a cross-sectional plan view of a mouthpiece of the presentinvention including extendable means between the vestibular shield andextra-oral sealing means, where the extendable means is in a contractedposition.

FIG. 19 is a cross-sectional plan view of a mouthpiece of the presentinvention including extendable means between the vestibular shield andextra-oral sealing means, where the extendable means is in an expandedposition.

FIG. 20 is an exploded perspective view of an alternative form of themouthpiece of the present invention including alternative extendablemeans between the vestibular shield and extra-oral sealing means.

FIG. 21 an exploded perspective view of the alternative form of themouthpiece of the present invention showing the gases passageway andsleeve that form the extendable means.

FIG. 22 is a perspective view of the alternative form of the mouthpieceof the present invention showing the gases passageway and sleeve inassociation.

FIG. 23 is a cutaway view of an alternative embodiment of the mouthpiecewith an outer flap in use, and an inner shield in the mouth cavityproper, behind the teeth, with an outlet valve mounted on the elbowjoint.

FIG. 24 is a cutaway view of an alternative embodiment of the mouthpiecewith a shield in the mouth cavity proper and a vestibular shield, withan outlet valve mounted on the elbow joint, and no extra-oral sealingmeans.

FIG. 25 is a perspective view of another alternative embodiment of amouthpiece with an alternative adjusting mechanism between the outerflap and vestibular shield.

FIG. 26 is a perspective view of a further alternative embodiment of themouthpiece of the present invention where the mouthpiece has yet anotherform of threaded adjustable mechanism to adjust the distance between thevestibular shield and outer flap.

FIG. 27 is a perspective partially exploded view of the mouthpiece ofFIG. 26.

FIG. 28 is a perspective fully exploded view of the mouthpiece of FIG.26, showing an over moulded ring attachment on the outer flap.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the invention may be susceptible to embodiment in different forms,specific embodiments are shown in the drawings and described in detailwith the understanding that the present disclosure is to be consideredan exemplification of the principles of the invention, and is notintended to limit the invention to that as illustrated and described.

The present invention provides a system for oral delivery of gasespressurised above ambient to a user and is especially suited for use inthe oral delivery of air in continuous positive airway pressure (CPAP)treatments of sleeping disorders such as sleep apnoea. As shown in FIG.3, the system includes a mouthpiece 1 which is connected by a connection2 to a breathing circuit 3.

Gases Diffusing Shield

One preferred embodiment of the present invention is illustrated inFIGS. 4 to 6. In this embodiment, the mouthpiece 1 includes a vestibularshield 21 being a generally flat and generally rectangularly-shapedmember in front elevation having a curved profile that reflects thecurvature of a user's jaw and in turn the curvature of the labialvestibule region. A gases passageway extends through the vestibularshield from an inlet 22 to an outlet part 20 having two diffusingoutlets 23, 24. The mouthpiece 1 also has an outer flap 25 similar tothat described in relation to FIGS. 1 and 2 and that described in U.S.co-pending patent application Ser. No. 09/629,536.

The outer flap 25 is tapered and the wide open end is shaped to conformto the facial contours around the outside of the mask of a user. Thenarrow end terminates in an inlet 26 of substantially circular crosssection and which is attached on one side to a breathing or inspiratorytube and the other to a connector 27 that connects the outer flap 25 tothe vestibular shield 21. The connector 27 is made from a substantiallyrigid plastics material and broadens in cross-section from a circularend 34 to an elongated oval end 35 that is attached to the inlet 36 ofthe outlet part 20. In other forms of the present invention theconnector may be formed in a soft plastics material such as silicon, sothat it provides additional flexibility to the mouthpiece to enable themouthpiece to better conform to the user's face.

The outer flap 25 and vestibular shield 21 are preferably formed in asoft and supple material such as silicon. The connector 27 between theouter flap 25 and vestibular shield 21, and outlet part 20 are made of astiffer material, such as a hard plastics material, for example,polycarbonate. In the form shown in FIG. 4, attached to the outlet sideof the vestibular shield 22 are over moulding outlets 32, 33 that aremade from a supple material and that fit over the outlets 23, 24 of theoutlet part 20. When assembled, as the vestibular shield 21 is made froma supple material, the outlet part 20 is able to be pushed through theinlet 22 in the vestibular shield 21 and the outlets 23, 24 fit into theover moulding outlets 32, 33.

The outlet part 20 is a substantially tubular U-shaped piece, where thetop (or inlet 36) of the U is open and connected to the elongated end 35of the connector 27. The arms of the U form gases passageways that areoval in cross-section that lead to the outlets 23, 24 that pass gasesfrom the mouthpiece 1 into the user's mouth. In this manner the gasesflowing through the mouthpiece 1 flow through the inlet to the outerflap 37, through the connector 27, and are diverted through each of theoutlets 23, 24 and around the sides of the user's mouth. Hence the gasesflowing into the user's mouth are effectively diffused.

The purpose of splitting or diffusing the gases flow in this manner isto prevent the user's tongue from covering the outlet and disrupting orstopping the gases flow and thus treatment provided to the user. If theprior art mouthpiece shown in FIGS. 1 and 2 had no tongue depressor tokeep the user's tongue at the bottom of the user's mouth the user couldinadvertently during sleep allow their tongue to cover the gases outlet.With a diffused outlet such as that shown in FIG. 4 where at least twooutlets direct flows substantially to the sides of the users mouth asopposed to the centre of the mouth it is not possible for a user toplace their tongue inadvertently over both or even one of the outlets23, 24. Furthermore with the absence of a tongue depressor and thediffusion of gases flow the user is still able to lift their tonguebetween the two arms of the outlet part and moisten their mouth,preventing dryness of the mouth. Also by allowing movement of the userstongue the mouthpiece of the present invention the user can swallowwithout difficulty. As a consequence of these advantages the mouthpiecein this form proves to be more comfortable to a user.

It is preferred that the outlet part 20 is made from a hard plasticsmaterial, but it could be made of a softer plastics material such assilicon.

It will be appreciated that as well as providing a substantiallyairtight seal the addition of the outer flap 25 provides enoughcompressive force on the mouth to keep the mouthpiece and conduit inplace without the need for straps. This allows the administering of CPAPtherapy to be considerably less obtrusive than traditional methods.

A typical respiratory humidification circuit such as might employ thepresent invention is shown diagrammatically in FIG. 17, and includes therespirator 200, humidifier 201, and the associated respiratory breathingtubes 202 and 203. A user 204 under treatment is shown, with themouthpiece of any of the abovementioned embodiments 205, located in themouth of the user 204.

With reference to FIG. 4A, an abutment 28 and an area 29 are formedabove the outlet part 20, preferably in the vestibular shield 21, is inwhich the user may place his or her teeth. The abutment 28 preventsinadvertent movement of the users' teeth away from or off the area 29.The abutment 28 also assists in the maintaining of the vestibular shield21 between the users' lips and teeth retaining the mouthpiece in andabout the users' mouth.

A notch 30 is provided centrally in the upper edge of the vestibularshield 21 to accommodate the upper frenal attachment. A slight bead 31may be provided around the edge of the vestibular shield 21 for usercomfort, with the vestibular shield 21 otherwise being very thin foradditional suppleness.

Vestibular Shield with Apertures

In an alternative embodiment of the vestibular shield that may be usedwith the mouthpiece of the present invention is shown in FIG. 7. Thevestibular shield 40 has a plurality of ventilation apertures 41, 42extending out from the centre of the shield 40. The apertures areeffectively channels spaced over the diameter of the shield 40 and areprovided to allow moisture to move about the shield 40 to preventdryness of the inside of the user's mouth.

As already discussed the vestibular shield 40 is preferably made of asoft and supple material, such as silicon. The shield 40 is preferablythin and has channels such as that shown in FIG. 7, although other formsof apertures or channels may be possible such as the shield being formedfrom a porous material or holes or slots being formed in the shield. Itis preferred that the shield has a textured finish at least on itsinside. The channels and the textured finish therefore allow formoisture to move around the vestibular shield and move from inside theshield to prevent dryness on the inside of the patient's mouth and toprevent the shield sticking to the inside of the patient's cheeks.

Another form of a vestibular shield having a diffusing outlet that maybe used with the mouthpiece of the present invention is shown in FIGS.11 to 13. This vestibular shield 50 is preferably used with the outerflap 25 as described above. The shield 50 has a notch 51 for the upperfrenal attachment and may have a bead 52 provided around the edge of theshield 50, similar to that of FIGS. 4 and 7. A diffused outlet 54 isformed in the vestibular shield 50 such that gases received from theinlet 53 move into an elongated recess 58 formed in the central area ofthe shield 50. There are a number of outlets 55, 56 formed in the innerwall 57 of the shield 50. Extending from the outer wall of the shield 50is a preferably tubular shield inlet 58 that is connected to the outerflap 25 via inlet 37, preferably by threaded connection, but other meansof attachment may be used. In use, gases flow from the inlet 37 of theouter flap 25 through the shield inlet 58, into the elongated recess 59formed in the central area of the shield 50 and out of the diffusingoutlets 55, 56 into the user's mouth.

Adjustable Mouthpiece

A further form of the mouthpiece of the present invention is shown inFIGS. 18 and 19. Here the mouthpiece 300 includes adjustment means 301located between the vestibular shield 302 and outer flap 303 that allowsfor the distance to be altered between the shield 302 and flap 303, toallow for adjustment dependant on a user's facial contours. Theadjustment means 301 is formed in the tubular gases passageway 301between the vestibular shield 302 and outer flap 303. The adjustmentmeans are bellows, corrugations or accordion like pleats 305 formed inthe walls of said tubular passageway 304. The pleats 305 allow for thevestibular shield 302 and outer flap 303 to be moved apart or pushedtogether to accommodate varying user's mouths and facial contours. Inuse, the pleats 305 may be extended from a contracted position (as shownin FIG. 18) to a fully extended position (as shown in FIG. 19) and viceversa. Furthermore, the user may extend or contract the pleats 305 toany position in between the fully extended or contracted position andthe mouthpiece 300 will stay in that position due to the stiffness ofthe material that the pleats are formed in. In the preferred form ofthis mouthpiece the tubular passage and pleats are formed in a stiffplastics material.

Referring now to FIG. 16, use of the mouthpiece according to FIGS. 4 to6 is depicted. With the present mouthpiece 1, the vestibular shield 21sits inside the user's lips 90, 91 and the outer flap 25 sits about theoutside of the user's lips. Thus a seal is formed by the pressure causedby the outer flap on the outside of the users' lips and the opposingforces of the vestibular shield on the inside of the users' lips. Oncethe mouthpiece 1 is correctly positioned in the mouth 93, the outer flap25 may be adjusted into its operational position by pressing on itsouter periphery until it snaps back and depresses against the outside ofthe mouth. Due to the relative position of the vestibular shield 21 andthe outer flap 25, the outer flap is unable to fully reach its naturalbias and thereby inflicts the compressive force on the outside of theusers' mouth.

As is illustrated in FIG. 16 the abutment 28 prevents the user's top rowof teeth 94 from slipping from the mouthpiece and therefore assists inpreventing accidental removal of the mouthpiece. Although not shown inFIG. 16, an additional abutment on the lower side of the mouthpiece maybe provided to stop the lower row of teeth from slipping from themouthpiece.

An alternative form of the mouthpiece of the present invention is shownin FIGS. 20 to 22. Here the mouthpiece 400 includes an alternativeadjustment means 401, to that shown in FIGS. 18 and 19. This form of theadjustment means 401 is the association of a sliding sleeve 402 with thetubular gases passageway 403. In this form the adjustment means 401 islocated between the vestibular shield 404 and outer flap 405, and allowsfor the distance to be altered between the shield 404 and flap 405.

The sleeve 402 is attached to the flap 405 by way of an interferencefit. Although not shown in the figures the flap 405 may during itsmoulding be over-moulded about the sleeve 402.

The gases passageway 403 shown in FIGS. 20 and 21 has at one end acircular opening 406 and the other end two oval exit ports 407, 408 thatdeflect gases passing through the mouthpiece to the sides of a patient'smouth, similar to those ports described in relation to FIGS. 4 to 6. Thevestibular shield 404 is associated with the tubular passageway 403 byfitting the tubular gases passageway 403 through the aperture 414 in theshield 404. Due to the flexible nature of the material the shield 404 ismade from, the shield 404 fits snugly about the tubular passageway 403,which does not allow for gases to leak through the aperture 414.

The gases passageway 403 has a series of elongate indentations 413provided on its outer surface at its circular opening end 406. Althoughnot shown, a set of diametrically opposed indentations similar to thoseindicated as 413 are provided on the passageway 403. The passageway 403also has two diametrically opposed elongate protrusions (of which onlyone protrusion 422 is shown in FIGS. 20 and 21) located on its outersurface nearer the circular opening end 406. These elongate protrusions422 are offset from the indentations 413 and are preferably spacedaround the circumference of the gases passageway such that a 90 degreeangle would be formed between each set of indentations and each elongateprotrusion.

The gases passageway 403 also has at least one stop projection 423located on its body. Preferably the stop projection 423 is integrally onthe gases passageway 403 when it is moulded. The projection 423 abutsagainst the upper edge of the sleeve 402 and prevents the sleeve 402from travelling too far along the gases passageway 403.

The sleeve 402 is preferably tubular in shape and made from a plasticmaterial. The tubular shape of the sleeve 402 allows for the sleeve tobe deformed, even though non-malleable plastics materials such aspolycarbonate are used. To assist with the deformation of the sleeve 402cantilever extensions 411, 412 are provided on the sleeve 402. Theseensure that the sleeve can be deformed without the sleeve 402 crackingor breaking.

The sleeve 402 has an inner skirt 415 and an outer portion 424. Theouter portion 415 is a circular tubular section that is integrallyformed with the skirt 415. The skirt 415 has two protrusions 409, 410that extend from the inner surface of the skirt 415 toward the centralaxis through the sleeve. In particular, during forming of the sleeve402, the skirt 415 and outer portion 424 are fused together at theprotrusions 409, 410. The protrusions 409, 410 are formed on one outeredge of the skirt 415 and link to the outer portion 424. The cantileverextensions 411, 412 are integrally formed on the other edge of the skirt415 during moulding and key hole apertures 427, 428 are formed in theskirt 415 that extend partially into the cantilever extensions 411, 412.The purpose of the key hole apertures 427, 428 are to prevent the sleeve402 from disengaging from the gases passageway 403 after beingassembled. Once the sleeve 402 is assembled about the gases passageway403 the nodules 425, 426 are located within the key hole apertures 427,428 and are able to slide within the apertures 427, 428, but prevent thesleeve 402 being removed from the gases passageway 403 as they abutagainst the ends of the apertures 427, 428. Although not apparent inFIGS. 20 to 22, complimentary keyhole apertures and nodules are providedon the diametrically opposed sides of the gases passageway 403 andsleeve 402.

Each of the protrusions 409, 410 and extensions 411, 412 are formed ondiametrically opposed sides of the sleeve 402. Elongated apertures 416,417 are formed on the inner surface of the skirt 415. The apertures 416,417 are diametrically opposed and are formed in the skirt 415 at aposition on the circular skirt that is 90 degrees from the diametricallyopposed protrusions 409, 410.

The outer portion 415 of the sleeve 402 has regions 418, 419 that arediametrically opposed and are thicker in width than the rest of theouter portion. These regions 418, 419 are effectively finger pads thatmay be provided with small protrusions 420, 421 or the like that allowfor traction between a user's fingers and the regions 418, 419.

The regions 418, 419 are offset from the protrusions 409, 410 such thatif sidewise forces A and B (shown in FIG. 22) are placed on the fingerpad regions 418, 419 the sleeve is deformed from a circular shape to amore elongated oval shape. As the regions 418, 419 and protrusions 409,410 are offset from one another when the regions are depressed orsqueezed together the protrusions 409, 410 on the sleeve 402 are pushedupwards and away from each other.

When assembled, the mouthpiece of the alternative form as shown in FIGS.20 to 22, the sleeve 402 fits about the tubular passageway 403. Thesleeve is prevented from moving to the exit port end of the passageway403 by the edge of the sleeve 402 abutting the projections 423. Thefitting of the elongate protrusions 422 into the elongated apertures416, 417 formed in the inner skirt 415 of the sleeve 402 preventrotation of the sleeve 402 and outer flap 405 relative to the gasespassageway 402.

In use, a user may adjust the mouthpiece 400 by squeezing the regions418, 419 wherein the protrusions 409, 410 extending from the innersurface of the skirt 415 are released from one of the indentations 413.The user may then slide the sleeve 402 and outer flap 405 along thegases passageway 402 and release the regions 418, 419 whereby theprotrusions 409, 410 will be released back into an alternative one ofthe indentations 413. Therefore, the distance between the shield 404 andouter flap 405 can be reduced or increased depending on the user'srequirements in this manner. In the preferred form there are threeindentations 413, as shown in FIG. 20, where each of these relates toone of three positions that a patient can adjust the distance betweenthe shield 404 and outer flap 405. In other forms of the mouthpiece 400the gases passageway may be provided with any number of indentations.

Referring now to FIG. 25, a further form of the adjustment mechanism isshown. The adjustment mechanism may be similar to that described above,but having a different locking mechanism. For example, the mouthpiecewould be very similar to the form of that shown in FIG. 21, but theslideable sleeve 402 of FIG. 21 would be replaced by the alternativesliding sleeve 1000. Thus the slideable sleeve 1000 would be fitted to asimilar tubular passageway 403 as shown in FIG. 21. The sleeve 1000 hasa similar working mechanism to that of the slideable sleeve 402 and hasprotrusions 1001, 1002 that fit into the apertures 413 on the tubularpassageway 403, which cause locking of the slideable sleeve 1000 on thepassageway 403 (compare with protrusions 409 on FIG. 21). Theprotrusions 1001, 1002 can be caused to move out of the apertures 413 byplacing an inward force on complimentary and opposing flexibleprotrusions 1003, 1004. Therefore, when a user squeezes the flexibleprotrusions 1003, 1004, the locking protrusions 1001, 1002 move out ofone of the apertures 413. The sleeve 1000 can then be slid along thetubular passageway 403 and the flexible protrusions 1003, 1004 released,causing the locking protrusions 1001, 1002 to enter another of theapertures 413. This causes the distance between the outer flap andvestibular shield to be adjusted.

Yet another form of adjustment mechanism between the vestibular shieldand outer flap is shown in FIGS. 26 to 28. Here the mouthpiece 900 hasan adjustment mechanism or means that is a threaded connection, whichallows for the distance to be altered between the vestibular shield 901and outer flap 902, to allow for adjustment dependent on a user's facialcontours. A thread is formed in the tubular gases passageway 904 betweenthe vestibular shield 901 and outer flap 902. The outer flap 902 has amoulded ring or bezel 906 having an inner thread 907. The ring 906 ispreferably permanently attached (for example, clipped to) a ringattachment means 908 in which the outer flap 902 is over moulded about.The ring or bezel 906 is capable of rotating about the ring attachmentmeans 908. As described the outer flap 902 is moulded over the ringattachment means 908. The edge 910 of the moulded outer flap 902 mayextend out from the ring attachment means 908 to create interferencebetween the outer flap 902 and the ring 906. Therefore, the amount offriction created between the ring 906 and the outer flap 902 can becontrolled dependent on how far out the outer flap 902 extends. Thefriction created prevents the ring 906 from freely rotating.

In use, the ring attachment means 908 is slid about the threaded gasespassageway 904 and causes the outer flap 902 and shield 901 to bealigned by the alignment of a protrusion 909 on the tubular passageway904. The protrusion 909 is aligned with and runs along the track 903formed in the thread 905 on the tubular passageway 904. As the tubularpassageway 904 and ring attachment means 908 are both made from a hardplastics material (such as, polycarbonate) they can be slid against oneanother. The thread 907 on the ring 906 meets with the thread 905 on thepassageway 904 and by rotating the ring 906 on the ring attachment means908, the ring attachment means 908 and outer flap 902 are moved towardsthe vestibular shield 901. As the threaded ring 907 progresses along thethreaded passageway 904 the distance between the vestibular shield 901and outer flap 902 is reduced or increased dependent on the user'srequirements. The capability of the ring 906 to rotate on the ringattachment means 908 means the distance between the vestibular shield901 and outer flap 902 can be altered into an infinite number ofpositions.

The mouthpiece embodiments described above that provide for fitting oradjustment of the distance between the outer flap and vestibular shieldall allow for adjustment while a patient's is wearing the mouthpiece.Therefore, one inserted in the patient's mouth the adjustment mechanismcan be used to tighten or loosen the mouthpiece to allow for optimumpatient comfort while maintaining the compressibility between the shieldand flap to retain the mouthpiece in the patient's mouth.

Elbow Connector

Attention is now directed to FIG. 3. It has been found that anadditional factor in the effectiveness of any mouthpiece, includingmouthpiece 1, is the manner in which the mouthpiece is connected to thebreathing circuit 3. The weight of the breathing circuit 3, and anyattempted movement of one other of the breathing circuit 3 and themouthpiece 1 relative to the other, is one of the largest influencestending to dislodge a mouthpiece 1 from the mouth of a user. It must benoted that the mouthpiece 1 must remain in position and maintain a sealduring all sleep when the user has no muscle tone.

The connection 2 as provided in the present invention between thebreathing circuit 3 and the mouthpiece 1 decouples the mouthpiece 1 fromthe breathing circuit 3. As a result, the connection 2 is effective inreducing the forces placed on the mouthpiece 1 by the breathing circuit3 when the user moves around during sleep. In the preferred sleepingposition, the breathing circuit 3 is laid across the chest 4 of theuser, and may be secured to the user's bed clothes or sleeping garments.The breathing circuit 3 is preferably laid on the chest of the user totake the weight of the breathing circuit 3 off of the mouthpiece 1.

To connect between the gases outlet 5 which is vertical when the user islying on his or her back and the breathing circuit 3 which is generallyhorizontal, an L-shaped elbow 6 is incorporated in the connection 2. Theelbow 6 is formed at a right angle and provides a positive pressure onthe mouthpiece 1 to maintain the mouthpiece 1 in the user's mouth. Theelbow 6 may include a swivel joint and may be disconnected from gasesoutlet 5. The connection 2 further includes an extremely flexibleconnecting tube 7 provided between the elbow 6 and the breathing circuit3. The connecting tube 7 is preferably connected to the breathingcircuit 3 by a swivel joint 8. The elbow swivel joint 6 allows formovement of the connection tube 7 relative to the mouthpiece 1. Theswivel joint 8 allows for movement of the connection tube 7 relative tothe breathing circuit 3. It is to be understood that one or both of theswivel joints 6, 8 could be eliminated, but the preferred embodimentincludes swivel joint 8.

Referring to FIG. 14 an alternative form of the elbow described above isshown. In this form the elbow piece 70 is shown as attached to aconnecting tube 71. The elbow piece 70 has an outlet 72 attached to theinlet of a mouthpiece (37 on FIG. 4) such that gases flow through theconnection tube 71 through the elbow piece 70 and out the outlet intothe mouthpiece and subsequently into the user's mouth. The elbow pieceis substantially L-shaped and preferably includes a swivel joint 73.Additionally a swivel joint may be provided on the connecting tube sideof the other connector, namely swivel joints 74. The end 75 distal tothe outlet is substantially tubular in shape and tapers from a widerdiameter at the joint 74 and narrows towards the connecting tube 71disposed along the length of a diffusing part 75 are elongate apertures76 that are also preferably tapered and shaped rather at the joint 74end and narrowing toward the connecting tube 71. A plurality of theseapertures 76 are disposed about the diffusing part and allow for gasesexhaled by the user through the mouthpiece and outer connector todiffuse into the ambient air. The tapered apertures also have theadditional advantage of diffusing the gases in a direction along theconnection tube 71 and therefore away from the user. Also these gasesflow away from anyone who may be facing the user, such as the user'spartner, for example, during sleeping. Additionally the diffuser 75 alsoallows for low noise diffusion of exhaled gases.

Referring now to FIG. 15, which shows a further alternative form of anelbow that may be used with a mouthpiece of the present invention. Theelbow 80 again is substantially L-shaped and connects at an outlet end81 to the inlet of a mouthpiece. The inlet 82 is connected to aconnecting piece of tube such as that shown in FIG. 3 or the connectingtube 71 of FIG. 14). In this embodiment the elbow connector 80 hasdiffusing means formed on a ledge 83 formed by the reduction in thediameter from the body 84 of the elbow 80 and the inlet piece 82. In usegases flow in through the inlet 82 in the direction of arrow A andexhaled gases are diffused out the plurality of apertures formed aboutthe circular ledge 83 (although only one aperture 85 is labelled it ispreferred that a number of apertures are formed about the circularledge. Due to the high pressure of the incoming gases the lower pressureoutgoing gases cause less effect as they are pushed to the edges and outthe apertures 85 on the incoming disk in the direction of arrow B.Again, like the embodiment of the other as shown in FIG. 4 the exhaledgases are directed away from the user and the user's partner and thenoise of gases diffusing is reduced.

Nose Flap and Attachments

Reference is now made to FIGS. 8 to 10 in which further embodiments of amouthpiece with nose flap or other attachments are illustrated.

Referring first to FIG. 8 a mouthpiece 800 is shown that has a blockingmember or attachment 801 extending from the outer flap 802. The blockingmember 801 has a curved or cut out region 803 such that when themouthpiece is in use in a patient's mouth the blocking member 801 restsagainst the patient's nose and blocks off the patient's nostrils. Theblocking member 801 has the purpose of preventing leakage of gases fromthe patient's nose when they are receiving treatment, such as receivingcontinuous positive pressure gases, via the mouthpiece. In the preferredform of this mouthpiece 800 the blocking member 801 is integrally formedwith the outer flap in silicone. In other forms the blocking member maybe made from other materials, such as foam, and separately attached, byway of gluing or the like, to the outer flap.

In another embodiment, as shown in FIGS. 9 and 9A, a mouthpiece 804 maybe provided with an outer flap 805 having a nose flap 806 that in useextends over and about the patient's nose. The nose flap 806 is mouldedwith the outer flap 805, preferably out of silicone, but otherappropriate materials may be used. The nose flap 806 is contoured to theapproximate shape of the human nose and has a lip or flange 807 aroundits edge to assist in the sealing of the nose flap 806 about a patient'snose, so as assist in the preventing of leaks from the nose. The lip orflange 807 continues around the perimeter of the outer flap to assist insealing of the flaps against the user's face.

In FIG. 9A we see a cross-section of the mouthpiece 804 of FIG. 9 withgases flowing through it shown by arrows. The gases flow from the tubing(such as the conduit 3, shown in FIG. 3) through an elbow connector 808and into the tubular passageway 809. The tubular passageway 809 has twooutlets in it, one outlet 810 that causes gases passing through thepassageway 809 to be directed to the oral cavity and other outlet 811 tothe nasal cavities. In this manner the patient has the option ofbreathing gases through either their nose or mouth. Expired gases fromthe patient are expelled through the outlet vent 812 on the elbowconnector. The mouthpiece with nose flap has the advantage of overcomingany leakages that may occur through the nose, when no flap or blockageis provided with a mouthpiece. Therefore, drying of the airway passagesand loss of pressure of the gases is reduced.

A further embodiment of a mouthpiece is shown in FIG. 9B. Here themouthpiece 813 has a similar nose flap 814 to that described withreference to FIG. 9A, but the passages to each of the nose and mouthcavities is separate not combined as in FIG. 9A. The nose flap 814 ispreferably moulded with a complete outer flap 815 and has a flange orlip 816 about its edge to assist with sealing of the nose flap 814 aboutthe patient's nose. The elbow connector 817 has an extension part 818that fits to an inlet 819 of the nose flap 814 so that gases aredirected to the passageway 820 formed inside the nose flap 814, butgases are also directed into the tubular passageway 821 in the usualmanner.

Another embodiment of a mouthpiece is shown in FIG. 9C. Here themouthpiece is identical to that of FIG. 9C, but has additional nasalcannula 822 attached to the inlet 819 to the nose flap 814. The nasalcannula 822 (of which only one of a pair is shown) in use would extendinto the patient's nares. The cannula 822 would assist in directinggases into the nasal cavities and also reduce leakage of gases. Also,with this mouthpiece a patient using the mouthpiece will have the optionto breathe nasally or orally.

Yet another embodiment of a mouthpiece is shown in FIG. 9D. Themouthpiece 823 is very similar to that of FIG. 9C but has no nose flap.Here the nasal cannula 824 provide for sealing in the nares and preventleakage. The connection between the connector 825 and the cannula mayhave an extension mechanism, such as bellow like corrugations 826 formedin the plastics material that the cannula 824 are formed from. Thebellows allow the cannula to be adjusted in length and always provide aforce toward the nose because of the mechanical and geometricalproperties of the bellows in the silicone, so that they can be fitted todifferent sized and shaped patients. Also, the bellows would enable thecannula 824 to be moved or adjusted to better fit particular patientsand assist user comfort. In the preferred form of the mouthpiecedifferent sizes of cannula may be provided with the mouthpiece. Thecannula can therefore be detached and different sized cannula fitted toallow fitting of the mouthpiece and cannula to fit different shapednoses. In the preferred form the cannula are made from a soft material,such as silicone.

Finally, FIG. 10 shows an outer flap 827 for a mouthpiece 828 havingprotrusions 828, 829 extending out from the upper edge 830 of the outerflap 827. The protrusions would in use rest against the outer regions ofa patients nose and press the outer edges of the nose inwards topartially or fully block the patient's nares. This would also have theeffect of preventing leakage from the patient's nares. The protrusionsare preferably made from a soft material such as silicone.

This flap 827 may be used with any of the mouthpieces previouslydescribed except for the mouthpieces having the nasal cannula or nasalflap.

In other forms of the mouthpiece a nose flap or blocked cannula may beprovided to seal and prevent breathing through the nose by eitherblocking the nose by applying pressure on the outside of the nose toforce the nares closed, squeezing the sides of the user's nose, coveringthe user's nares or in the case of a cannula, by being inserted into theuser's nose.

Mouth Cavity Proper Shield

Two alternative embodiments of the mouthpiece will now be described,with particular reference to FIGS. 23 and 24. Both alternativeembodiments feature a paired shield or flap arrangement, similar to thatalready described for the outer flap and vestibular shield pairing.

In the first alternative embodiment, as shown in FIG. 23, vestibularshield 21 of FIG. 4 is replaced by a shield 601, located in the mouthcavity proper 607 (hereto forward referred to as the MCP shield 601),which is paired with an outer flap 602. The MCP shield 601 is designedto sit in the mouth cavity proper, between the teeth and the tongue. Inall other respects, it fulfils the same gas diffusion and sealingfunctions as have already been outlined for the different embodiments ofthe vestibular shield.

In this preferred embodiment, the MCP shield 601 is a generally flat andgenerally rectangularly-shaped member in front elevation having a curvedprofile that reflects the curvature of a user's jaw and in turn thecurvature of the mouth cavity region. A gases passageway 603 extendsthrough the mouthpiece and has an outlet 604 exiting through the MCPshield 601. The outlet 604 can be configured so that the gases arediffused in a similar manner to that already described, or the MCPshield 601 may be fitted with a plurality of ventilation apertures asalready described for the vestibular shield. The mouthpiece 1 also hasan outer flap 602 similar to that already described. The inlet 605 andconnector 606 are also similar to the embodiments already described.

The MCP shield 601 is preferably formed in a soft and supple materialsuch as silicon. The connector 606 between the outer flap 602 and MCPshield 601, and outlet part 604 are made of a stiffer material, such asa hard plastics material, for example, polycarbonate, in order toprevent an inadvertent squeezing or pinching closed of the connector 606by the teeth 608 or lips 609 of the user if the user unconsciouslyattempts to close their mouth during sleep.

In the second alternative embodiment, as shown in FIG. 24, themouthpiece 1 consists of a vestibule guard 702, paired with a shield 701located in the mouth cavity proper 707 (hereto forward referred to asthe MCP shield 701), and a connector 706 with outlet 704. There is noouter flap in this embodiment. The vestibular guard 702 in thisembodiment contains no gases diffusing means, or apertures or channels,and is preferably formed in a soft and supple material such as silicon.The MCP shield 701 is designed to sit in the mouth cavity proper,between the teeth 708 and the tongue 705, and fulfils the same gasdiffusion and sealing functions as have been outlined for the vestibularguard 21 of FIG. 4 in the preferred embodiment. The connector 706 ismade of a stiffer material, such as a hard plastics material, forexample, polycarbonate, in order to prevent an inadvertent squeezing orpinching closed of the connector 706 by the teeth 708 or lips 709 of theuser if the user unconsciously attempts to close their mouth duringsleep.

In both of the alternative embodiments described above, the mouthpiece 1can include an adjusting means such as the bellows extension previouslydescribed and shown in FIGS. 18 and 19, and a connection to thebreathing circuit via an elbow connector as already described. In theembodiments shown, the elbow connector includes an outlet valve, shownas component 610 in FIG. 23 and component 710 in FIG. 24. In alternativeembodiments, the outlet valve may be replaced by either of thealternative gas diffusion arrangements as already described. Also, inthe embodiment shown in FIG. 23, a nose flap as previously described maybe included.

ADVANTAGES

From the above it can be seen that the present invention provides asystem including a mouthpiece for oral delivery of CPAP treatment whichonce is low cost and effective. Unlike other mouthpieces the mouthpieceof the present invention does not require custom orthodontic fitting, asthe mouthpiece does not rely on accurate alignment with the user's teethor the user's palate to provide location and retention within the user'smouth. In the preferred embodiment the mouthpiece resides in thevestibule between the teeth and lips and the teeth and cheeks, and thelateral and vertical extension of a vestibular shield requires that theuser's lips be actively manipulated for the vestibular shield to beremoved. Furthermore the vestibular shield is provided with an outletthat allows for diffusion of the gases provided to the user and thus themouthpiece does not require any tongue depressor. The mouthpiece andvestibular shield thus prevent a user blocking the flow of gases fromthe mouthpiece, yet is more comfortable for the user than prior artdevices. With the addition of the extra-oral flap the mouthpiece andassociated tubing is held securely in place without the need forexternal strapping, and an effective seal is created around the user'smouth.

Similar advantages are conferred by the alternative embodimentsoutlined, where the paired shield arrangements are located eitherextra-orally and in the mouth cavity proper, or as a paired vestibularshield and mouth cavity proper shield. In both of these alternativeembodiments, accurate location and retention in a user's mouth isachieved, requiring a conscious effort by the user to remove themouthpiece. In both of these embodiments, an outlet that allows fordiffusion of the gases is provided that does not require any tonguedepressor and the paired shield arrangement ensures that the airflowwill occur substantially through the gases passageway, with littleleakage.

What is claimed is:
 1. An apparatus for supplying breathing gases from agases supply to a user through a breathing circuit to provide anelevated internal pressure in the user's airways, the apparatuscomprising: a first portion configured to contact the user at a firstlocation, the first portion defining an opening that accommodates a flowof breathing gases; a second portion configured to contact the user at asecond location; an adjustment mechanism that permits adjustment of thesecond portion relative to the first portion along an adjustment axis toa selected one of a plurality of discrete adjustment positions such thatthe apparatus can be adjusted to the user's facial contours, wherein theadjustment mechanism comprises: an adjuster comprising a circularportion, a pair of cantilever extensions coupled to the circularportion, and a pair of adjustment protrusions extending in a radialdirection relative to the circular portion, wherein the adjustmentprotrusions are diametrically opposed from one another; a plurality ofindentations that define the plurality of discrete adjustment positions;wherein each of the pair of adjustment protrusions is configured toengage a selected one of the plurality of indentations to secure thefirst portion and the second portion in the selected one of theplurality of discrete adjustment positions, and wherein each of the pairof adjustment protrusions is deflectable in a radial direction to permitthe adjustment protrusions to be disengaged from the selected one of theplurality of indentations and moved to another one of the plurality ofindentations to secure the first portion and the second portion inanother one of the plurality of discrete adjustment positions; a pair ofslots defined by one of the first portion and the second portion thatextend in a direction parallel to the adjustment axis, wherein the pairof slots are more closely spaced in a circumferential direction than thepair of adjustment protrusions; a pair of retention protrusions, whereineach of the pair of retention protrusions is received within one of thepair of slots, wherein the retention protrusions contact an end surfaceof a respective one of the pair of slots to limit movement of the secondportion relative to the first portion along the adjustment axis tomaintain engagement of the first portion and the second portion; anelbow connector configured to connect the breathing circuit to theapparatus, wherein the elbow connector comprises a swivel joint; anoutlet vent that permits expired gases from the patient to be expelledfrom the apparatus.
 2. The apparatus of claim 1, wherein the firstportion and the second portion are each constructed at least in part ofa polycarbonate material.
 3. An apparatus for supplying breathing gasesfrom a gases supply to a user through a breathing circuit to provide anelevated internal pressure in the user's airways, the apparatuscomprising: a first portion configured to contact the user at a firstlocation, the first portion defining an opening that accommodates a flowof breathing gases; a second portion configured to contact the user at asecond location; an adjustment mechanism that permits adjustment of thesecond portion relative to the first portion along an adjustment axis toa selected one of a plurality of discrete adjustment positions such thatthe apparatus can be adjusted to the user's facial contours, wherein theadjustment mechanism comprises: an adjuster comprising a circularportion, a pair of cantilever extensions coupled to the circularportion, and a pair of protrusions extending in a radial directionrelative to the circular portion; a plurality of indentations thatdefine the plurality of discrete adjustment positions; wherein each ofthe pair of protrusions is configured to engage a selected one of theplurality of indentations to secure the first portion and the secondportion in the selected one of the plurality of discrete adjustmentpositions, and wherein each of the pair of protrusions is deflectable ina radial direction to permit the protrusions to be disengaged from theselected one of the plurality of indentations and moved to another oneof the plurality of indentations to secure the first portion and thesecond portion in another one of the plurality of discrete adjustmentpositions.
 4. The apparatus of claim 3, wherein the protrusions arediametrically opposed from one another.
 5. The apparatus of claim 3,wherein the adjustment mechanism further comprises at least onealignment protrusion on one of the first portion and the second portionand at least one alignment slot on the other one of the first portionand the second portion, wherein the at least one alignment protrusion isreceived within and slides along the at least one alignment slot duringthe movement of the second portion relative to the first portion tomaintain rotational alignment of the first portion and the secondportion.
 6. The apparatus of claim 5, wherein the at least one alignmentprotrusion comprises a first alignment protrusion and a second alignmentprotrusion and wherein the at least one alignment slot comprises a firstalignment slot and a second alignment slot.
 7. The apparatus of claim 3,wherein the adjustment mechanism further comprises a stop carried by thesecond portion that contacts the first portion to limit relativemovement of the first portion and the second portion along theadjustment axis.
 8. The apparatus of claim 3, further comprising anelbow connector configured to connect the breathing circuit to theapparatus.
 9. The apparatus of claim 8, wherein the elbow connectorcomprises a swivel joint.
 10. The apparatus of claim 3, furthercomprising an outlet vent that permits expired gases from the patient tobe expelled from the apparatus.
 11. The apparatus of claim 3, whereinthe first portion and the second portion are each constructed at leastin part of a polycarbonate material.
 12. An apparatus for supplyingbreathing gases from a gases supply to a user through a breathingcircuit to provide an elevated internal pressure in the user's airways,the apparatus comprising: a first portion configured to contact the userat a first location, the first portion defining an opening thataccommodates a flow of breathing gases; a second portion configured tocontact the user at a second location; an adjustment mechanism thatpermits adjustment of the second portion relative to the first portionalong an adjustment axis to a selected one of a plurality of discreteadjustment positions such that the apparatus can be adjusted to theuser's facial contours, wherein the adjustment mechanism comprises: anadjuster comprising a circular portion, a pair of cantilever extensionscoupled to the circular portion, and a pair of adjustment protrusionsextending in a radial direction relative to the circular portion; aplurality of indentations that define the plurality of discreteadjustment positions; wherein each of the pair of adjustment protrusionsis configured to engage a selected one of the plurality of indentationsto secure the first portion and the second portion in the selected oneof the plurality of discrete adjustment positions, and wherein each ofthe pair of adjustment protrusions is deflectable in a radial directionto permit the adjustment protrusions to be disengaged from the selectedone of the plurality of indentations and moved to another one of theplurality of indentations to secure the first portion and the secondportion in another one of the plurality of discrete adjustmentpositions; a first pair of radial protrusions; and a second pair ofradial protrusions, wherein each of the first and second pair of radialprotrusions are more closely spaced in a circumferential direction thanthe pair of adjustment protrusions.
 13. The apparatus of claim 12,wherein the protrusions are diametrically opposed from one another. 14.The apparatus of claim 12, further comprising an elbow connectorconfigured to connect the breathing circuit to the apparatus.
 15. Theapparatus of claim 16, wherein the elbow connector comprises a swiveljoint.
 16. The apparatus of claim 12, further comprising an outlet ventthat permits expired gases from the patient to be expelled from theapparatus.
 17. The apparatus of claim 12, wherein the first portion andthe second portion are each constructed at least in part of apolycarbonate material.
 18. The apparatus of claim 12, wherein thecircular portion of the adjuster further comprises a pair of elongatedapertures extending in a direction parallel to the adjustment axis. 19.The apparatus of claim 18, wherein the elongated apertures arediametrically opposed from one another.
 20. The apparatus of claim 19,wherein the elongated apertures are open at each end.